At least the good thing is you can run the same benchmark locally and figure out what went wrong. Anandtech posted similarly wonky results for Chromium compiles on Threadripper, but that one isn't reproducible.
I think they "explained" afterwards that they use an older version of Chromium that predates the switch to clang and spends all of it's time in the single-threaded MSVC linker. (Which immediately explains much of their results...)